Wind turbines and other structures can be subject to lightning strikes, which can potentially damage the structures themselves, damage electronic or other components supported by the structures, or result in other detrimental effects. Accordingly, it can be useful to provide wind turbines and other structures with lightning protection systems in order to appropriately route electrical current from lightning strikes to the ground.
Conventional lightning protection systems for wind turbines generally adopt one or more of three approaches for protecting wind turbine blades (here, generally, “blades”) from lightning strikes. A first conventional approach uses tip receptors, which are generally configured as cylindrical conductors that protrude through the distal fins of respective blades, or as conductive end caps that generally match the relevant blade profiles. Generally, a tip receptor is connected to a down conductor, or earthing electrode, which extend from a connection of the down conductor with the tip receptor, through an internal cavity of the turbine blade, to the blade root. Some conventional designs can also use an anchoring block, also referred to as a receptor block, that can be located within the blade cavity some distance away from the blade tip and can provide an electro-mechanical bonding junction for the tip receptor and the down conductor.
A second conventional approach uses conductive surface receptor disks, each with a respective exposed face and receptor body. A receptor body is generally recessed into the relevant blade wall and can sometimes extend into the relevant blade cavity. Generally, the exposed face of a receptor disk is circular, while the shape of the receptor body can vary. In some installations, receptor disks are disposed near the trailing edge of a blade. In some installations, several receptor disks can be arranged at various points along the length of the blade, with the number of receptor disks dependent upon the length of the blade. In some installations, sets of receptor disks can be disposed near the tip of a blade in lieu of a tip receptor (e.g., as described above).
A third conventional approach uses blade coverings, which are generally configured as conductive layers that extend over a relatively large area of the surface of a blade. The layers of the blade coverings can be formed as continuous solids, meshes, or cured resins. Generally, the blade coverings are applied in sheets, strips or patches, and can be placed on the exterior surface of a blade or just below a surface coating of the blade.